KR20070054806A - Organic light emitting diode display - Google Patents

Abstract

An organic light emitting diode display according to an exemplary embodiment of the present invention includes a substrate, a first signal line formed on the substrate, a second signal line intersecting the first signal line, a driving voltage line formed on the substrate, and transmitting a first voltage, and a first signal line; A first thin film transistor connected to the second signal line, a second thin film transistor connected to the first thin film transistor and a driving voltage line, a passivation layer formed on the first and second thin film transistors, a blocking layer formed on the passivation layer, and a blocking layer And a light emitting member formed between the first electrode, the second electrode facing the first electrode and receiving the second voltage, and the first electrode connected to the second thin film transistor. Therefore, the organic light emitting diode display according to the exemplary embodiment may block moisture flowing into the organic light emitting member by forming a blocking layer formed of an inorganic layer on the passivation layer formed of the organic layer. In addition, by forming the protective film as an inorganic film, the moisture content of the protective film is minimized to improve the life of the organic light emitting member.

OLED display, inorganic film, protective film, moisture

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DIODE DISPLAY}

1 is an equivalent circuit diagram of an organic light emitting diode display according to an exemplary embodiment of the present invention.

2 is a layout view of an organic light emitting diode display according to an exemplary embodiment.

3 and 4 are cross-sectional views of the organic light emitting diode display of FIG. 2 taken along lines III-III and IV-IV, respectively.

5 and 6 are cross-sectional views of an organic light emitting diode display according to another exemplary embodiment. The organic light emitting diode display of FIG. 2 is taken along line III-III and IV-IV.

<Description of the symbols for the main parts of the drawings>

110: substrate 121, 129: gate line

124a: first control electrode 124b: second control electrode

127: sustain electrode 140: gate insulating film

154a: first island semiconductor 154b: second island semiconductor

163a and 165a: first resistive contact member

163b and 165b: second resistive contact member

171 and 179: data line 172: driving voltage line

173a: first input electrode 173b: second input electrode

175a: first output electrode 175b: second output electrode

175: drain electrode 180: protective film

181, 182, 184, 185a, 185b: contact hole

191: pixel electrode 270: common electrode

361: partition 365: opening

370: organic light emitting member

81, 82: contact auxiliary member 85: connecting member

The present invention relates to an organic light emitting display device.

Recently, there is a demand for weight reduction and thinning of a monitor or a television, and according to such a demand, a cathode ray tube (CRT) has been replaced by a liquid crystal display (LCD).

However, the liquid crystal display device requires not only a separate backlight as a light emitting device, but also has many problems in response speed and viewing angle.

Recently, as a display device capable of overcoming such a problem, an organic light emitting diode display (OLED display) has attracted attention.

The organic light emitting diode display includes two electrodes and a light emitting layer disposed therebetween, and electrons injected from one electrode and holes injected from another electrode combine in the light emitting layer to excite excitons. And excitons emit light while releasing energy.

The organic light emitting diode display is not only advantageous in terms of power consumption because it does not need a separate light source, and also has excellent response speed, viewing angle, and contrast ratio.

In the organic light emitting diode display, a passivation layer for planarization is formed of an organic layer on the thin film transistor, and an organic light emitting member is formed on the passivation layer. In this case, the organic light emitting member is adversely affected by the moisture contained in the organic film.

An object of the present invention is to provide an organic light emitting display device which prevents damage to an organic light emitting member caused by an organic film.

An organic light emitting diode display according to an exemplary embodiment of the present invention includes a substrate, a first signal line formed on the substrate, a second signal line intersecting the first signal line, a driving voltage line formed on the substrate, and transmitting a first voltage; A first thin film transistor connected to a first signal line and the second signal line, a second thin film transistor connected to the first thin film transistor and the driving voltage line, a passivation layer formed on the first and second thin film transistors, and the passivation layer A blocking layer formed thereon, a first electrode formed on the blocking layer and connected to the second thin film transistor, a second electrode receiving a second voltage and facing the first electrode, the first electrode and the second electrode; It is preferable to include the light emitting member formed between electrodes.

In addition, the blocking layer may be formed of an inorganic film or a mixed thin film made of an inorganic insulator and an organic insulator.

In addition, it is preferable that the protective film and the blocking layer are alternately formed on the protective film and the blocking layer.

In addition, it is preferable to further include a partition wall surrounding the light emitting member.

In addition, an organic light emitting diode display according to an exemplary embodiment of the present invention includes a substrate, a first signal line formed on the substrate, a second signal line crossing the first signal line, and a driving voltage line formed on the substrate and transferring a first voltage. And a blocking layer formed on the first thin film transistor connected to the first signal line and the second signal line, the second thin film transistor connected to the first thin film transistor and the driving voltage line, and the first and second thin film transistors. And a first electrode formed on the blocking layer and connected to the second thin film transistor, a second electrode applied with a second voltage and facing the first electrode, and formed between the first electrode and the second electrode. It is preferable that the light-emitting member includes a blocking layer formed of an inorganic film.

Then, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

First, an organic light emitting diode display according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 1.

1 is an equivalent circuit diagram of an organic light emitting diode display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the organic light emitting diode display according to the present exemplary embodiment includes a plurality of signal lines 121, 171, and 172 and a plurality of pixels PX connected to the plurality of signal lines 121, 171, and 172 and arranged in a substantially matrix form. ).

The signal line includes a plurality of gate lines 121 for transmitting a gate signal (or scan signal), a plurality of data lines 171 for transmitting a data signal, and a plurality of driving voltage lines for transmitting a driving voltage. and a driving voltage line 172. The gate lines 121 extend substantially in the row direction, and are substantially parallel to each other, and the data line 171 and the driving voltage line 172 extend substantially in the column direction, and are substantially parallel to each other.

Each pixel PX includes a switching transistor Qs, a driving transistor Qd, a storage capacitor Cst, and an organic light emitting diode OLED. ).

The switching transistor Qs has a control terminal, an input terminal, and an output terminal. The control terminal is connected to the gate line 121, and the input terminal is a data line 171. ) And the output terminal is connected to the driving transistor Qd. The switching transistor Qs transfers the data signal applied to the data line 171 to the driving transistor Qd in response to the scan signal applied to the gate line 121.

The driving transistor Qd also has a control terminal, an input terminal and an output terminal, the control terminal being connected to the switching transistor Qs, the input terminal being connected to the driving voltage line 172, and the output terminal being the organic light emitting diode. It is connected to (LD). The driving transistor Qd flows an output current ILD whose magnitude varies depending on the voltage applied between the control terminal and the output terminal.

The capacitor Cst is connected between the control terminal and the input terminal of the driving transistor Qd. The capacitor Cst charges the data signal applied to the control terminal of the driving transistor Qd and maintains it even after the switching transistor Qs is turned off.

The organic light emitting diode LD has an anode connected to the output terminal of the driving transistor Qd and a cathode connected to the common voltage Vss. The organic light emitting diode LD displays an image by emitting light having a different intensity depending on the output current ILD of the driving transistor Qd.

The switching transistor Qs and the driving transistor Qd are n-channel field effect transistors (FETs). However, at least one of the switching transistor Qs and the driving transistor Qd may be a p-channel field effect transistor. In addition, the connection relationship between the transistors Qs and Qd, the capacitor Cst, and the organic light emitting diode LD may be changed.

Next, the detailed structure of the organic light emitting diode display illustrated in FIG. 1 will be described in detail with reference to FIGS. 2 to 4.

2 is a layout view of an organic light emitting diode display according to an exemplary embodiment, and FIGS. 3 and 4 are cross-sectional views of the organic light emitting diode display of FIG. 2 taken along lines III-III and IV-IV, respectively. .

A plurality of gates including a plurality of gate lines 121 including a first control electrode 124a and a plurality of second control electrodes 124b on an insulating substrate 110 made of transparent glass or plastic. A gate conductor is formed.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line 121 includes a wide end portion 129 for connection with another layer or an external driving circuit, and the first control electrode 124a extends upward from the gate line 121. When a gate driving circuit (not shown) generating a gate signal is integrated on the substrate 110, the gate line 121 may extend to be directly connected to the gate driving circuit.

The second control electrode 124b is separated from the gate line 121 and includes a storage electrode 127 extending downward and briefly changing to the right and extending upward.

The gate conductors 121 and 124b are made of aluminum-based metals such as aluminum (Al) and aluminum alloys, silver-based metals such as silver (Ag) and silver alloys, copper-based metals such as copper (Cu) and copper alloys, and molybdenum (Mo) It may be made of molybdenum-based metals such as molybdenum alloys, chromium (Cr), tantalum (Ta), and titanium (Ti). However, they may have a multilayer structure including two conductive films (not shown) having different physical properties. One of the conductive films is made of a metal having low resistivity, such as aluminum-based metal, silver-based metal, or copper-based metal, so as to reduce signal delay or voltage drop. On the other hand, other conductive films are made of other materials, particularly materials having excellent physical, chemical and electrical contact properties with indium tin oxide (ITO) and indium zinc oxide (IZO), such as molybdenum-based metals, chromium, titanium, tantalum, and the like. Good examples of such a combination include a chromium bottom film, an aluminum (alloy) top film, and an aluminum (alloy) bottom film and a molybdenum (alloy) top film. However, the gate conductors 121 and 124b may be made of various metals or conductors.

Side surfaces of the gate conductors 121 and 124b are inclined with respect to the substrate 110 surface, and the inclination angle is preferably about 30 ° to about 80 °.

A gate insulating layer 140 made of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate conductors 121 and 124b.

On the gate insulating layer 140, a plurality of first and second island-like semiconductors 154a and 154b made of hydrogenated amorphous silicon (amorphous silicon is abbreviated a-Si), polycrystalline silicon, or the like are formed. It is. The first and second semiconductors 154a and 154b are positioned on the first and second control electrodes 124a and 124b, respectively.

A plurality of pairs of first ohmic contacts 163a and 165a and a plurality of pairs of second ohmic contacts 163b and 165b are formed on the first and second semiconductors 154a and 154b, respectively. The ohmic contacts 163a, 163b, 165a, and 165b have an island shape, and may be made of a material such as n + hydrogenated amorphous silicon in which n-type impurities such as phosphorus are heavily doped or made of silicide. The first ohmic contacts 163a and 165a are arranged in pairs on the first semiconductor 154a, and the second ohmic contacts 163b and 165b are also arranged in pairs and disposed on the second semiconductor 154b.

The plurality of data lines 171, the plurality of driving voltage lines 172, and the plurality of first and second output electrodes 175a are disposed on the ohmic contacts 163a, 163b, 165a, and 165b and the gate insulating layer 140. , A plurality of data conductors including 175b are formed.

The data line 171 transmits a data signal and mainly extends in the vertical direction to cross the gate line 121. Each data line 171 has a wide end portion 179 for connection of a plurality of first input electrodes 173a extending toward the first control electrode 124a with another layer or an external driving circuit. It includes. When a data driving circuit (not shown) generating a data signal is integrated on the substrate 110, the data line 171 may be extended to be directly connected to the data driving circuit.

The driving voltage line 172 transfers a driving voltage and mainly extends in the vertical direction to cross the gate line 121. Each driving voltage line 172 includes a plurality of second input electrodes 173b extending toward the second control electrode 124b. The driving voltage line 172 overlaps the storage electrode 127 and may be connected to each other.

The first and second output electrodes 175a and 175b are separated from each other and also separated from the data line 171 and the driving voltage line 172. The first input electrode 173a and the first output electrode 175a face each other with respect to the first control electrode 124a, and the second input electrode 173b and the second output electrode 175b are the second control electrode. Facing each other around 124b.

The data conductors 171, 172, 175a, and 175b are preferably made of a refractory metal such as molybdenum, chromium, tantalum, and titanium, or an alloy thereof, and include a refractory metal film (not shown) and a low resistance conductive film (not shown). It may have a multi-layer structure including). Examples of the multilayer structure include a double layer of chromium or molybdenum (alloy) lower layer and an aluminum (alloy) upper layer, and a triple layer of molybdenum (alloy) lower layer and aluminum (alloy) interlayer and molybdenum (alloy) upper layer. However, the data conductors 171, 172, 175a, and 175b may be made of various other metals or conductors.

Like the gate conductors 121 and 124b, the data conductors 171, 172, 175a and 175b also preferably have their side surfaces inclined at an inclination angle of about 30 ° to 80 ° with respect to the surface of the substrate 110.

The ohmic contacts 163a, 163b, 165a, and 165b exist only between the semiconductors 154a and 154b below and the data conductors 171, 172, 175a, and 175b thereon, thereby lowering the contact resistance. The semiconductors 154a and 154b have portions exposed between the input electrodes 173a and 173b and the output electrodes 175a and 175b and not covered by the data conductors 171, 172, 175a and 175b.

A passivation layer 180 is formed on the data conductors 171, 172, 175a, and 175b and the exposed portions of the semiconductors 154a and 154b. The passivation layer 180 is made of an organic insulator having planarization characteristics. However, the passivation layer 180 may have a double layer structure of the lower inorganic layer and the upper organic layer so as not to damage the exposed portions of the semiconductors 154a and 154b while maintaining excellent insulating properties of the organic layer.

The blocking layer 186 is formed on the passivation layer 180. The blocking layer 186 is made of an inorganic film such as silicon nitride (SiNx) or silicon oxide (SiO 2). The blocking layer 186 prevents water generated from the passivation layer 180 formed of the organic layer from leaking to another layer.

In addition, the blocking layer 186 may be formed of a mixed thin film in which an organic insulator and an inorganic insulator are mixed. In order to further improve the moisture barrier property, the protective layer and the barrier layer may be alternately formed on the dual structure of the passivation layer 180 and the barrier layer 186.

In the passivation layer 180 and the blocking layer 186, a plurality of contact holes 182, 185a, and 185b exposing end portions 179 of the data line 171 and the first and second output electrodes 175b, respectively. And a plurality of contact holes exposing the end portion 129 of the gate line 121 and the second input electrode 124b in the passivation layer 180, the blocking layer 186, and the gate insulating layer 140, respectively. 181 and 184 are formed.

A plurality of pixel electrodes 191, a plurality of connecting members 85, and a plurality of contact assistants 81 and 82 are formed on the blocking layer 186. These may be made of a transparent conductive material such as ITO or IZO or a reflective metal such as aluminum, silver or an alloy thereof.

The pixel electrode 191 is physically and electrically connected to the second output electrode 175b through the contact hole 185b, and the connection member 85 is connected to the second control electrode 124b through the contact holes 184 and 185a. ) And the first output electrode 175a.

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 through the contact holes 181 and 182, respectively. The contact auxiliary members 81 and 82 compensate for and protect the adhesion between the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 and the external device.

A partition 361 is formed on the blocking layer 186. The partition 361 surrounds the edge of the pixel electrode 191 like a bank to define an opening 365 and is made of an organic insulator or an inorganic insulator. The partition 361 may also be made of a photosensitizer including a black pigment, in which case the partition 361 serves as a light blocking member and the forming process is simple.

An organic light emitting member 370 is formed in the opening 365 on the pixel electrode 191 defined by the partition 361. The organic light emitting member 370 is made of an organic material that uniquely emits light of any one of primary colors such as three primary colors of red, green, and blue. The organic light emitting diode display displays a desired image by using a spatial sum of the primary color light emitted by the organic light emitting members 370.

The organic light emitting member 370 may have a multilayer structure including an auxiliary layer (not shown) for improving the light emitting efficiency of the light emitting layer in addition to the light emitting layer (not shown) for emitting light. The auxiliary layer includes an electron transport layer (not shown) and a hole transport layer (not shown) for balancing electrons and holes, and an electron injection layer for enhancing the injection of electrons and holes ( electron injecting layers (not shown) and hole injecting layers (not shown).

In this case, since the blocking layer 186 is formed between the organic light emitting member 370 and the passivation layer 180, moisture generated in the passivation layer 180 made of the organic layer is prevented from entering the organic light emitting member 370. . Therefore, the lifespan of the organic light emitting member 370 can be improved.

The common electrode 270 is formed on the organic light emitting member 370. The common electrode 270 receives a common voltage Vss and is made of a reflective metal including calcium (Ca), barium (Ba), magnesium (Mg), aluminum, silver, or the like, or a transparent conductive material such as ITO or IZO. .

In the organic light emitting diode display, the first control electrode 124a connected to the gate line 121, the first input electrode 173a and the first output electrode 175a connected to the data line 171 may be formed. 1 together with the semiconductor 154a, a switching TFT Qs is formed, and a channel of the switching TFT Qs is formed between the first input electrode 173a and the first output electrode 175a. 1 is formed in the semiconductor 154a. The second control electrode 124b connected to the first output electrode 175a, the second input electrode 173b connected to the driving voltage line 172, and the second output electrode connected to the pixel electrode 191 ( 175b forms a driving TFT Qd together with the second semiconductor 154b, and a channel of the driving TFT Qd is formed between the second input electrode 173b and the second output electrode 175b. It is formed in the second semiconductor 154b. The pixel electrode 191, the organic light emitting member 370, and the common electrode 270 form an organic light emitting diode LD, and the pixel electrode 191 is an anode and the common electrode 270 is a cathode. Alternatively, the pixel electrode 191 becomes a cathode and the common electrode 270 becomes an anode. The storage electrode 127 and the driving voltage line 172 overlapping each other form a storage capacitor Cst.

The organic light emitting diode display emits light toward the top or the bottom of the substrate 110 to display an image. The opaque pixel electrode 191 and the transparent common electrode 270 are applied to a top emission type organic light emitting display device that displays an image in an upward direction of the substrate 110. The opaque common electrode 270 is applied to a bottom emission organic light emitting display device that displays an image in a downward direction of the substrate 110.

On the other hand, when the semiconductors 154a and 154b are polycrystalline silicon, an intrinsic region (not shown) facing the control electrodes 124a and 124b and an impurity region (extrinsic region) located at both sides thereof are not shown. Not included). The impurity region is electrically connected to the input electrodes 173a and 173b and the output electrodes 175a and 175b, and the ohmic contacts 163a, 163b, 165a and 165b may be omitted.

In addition, the control electrodes 124a and 124b may be disposed on the semiconductors 154a and 154b, and the gate insulating layer 140 may be positioned between the semiconductors 154a and 154b and the control electrodes 124a and 124b. In this case, the data conductors 171, 172, 173b, and 175b may be disposed on the gate insulating layer 140 and may be electrically connected to the semiconductors 154a and 154b through contact holes (not shown) bored in the gate insulating layer 140. . Alternatively, the data conductors 171, 172, 173b, and 175b may be positioned under the semiconductors 154a and 154b to be in electrical contact with the semiconductors 154a and 154b thereon.

On the other hand, the protective film can be directly formed of an inorganic film having flattening properties. 5 and 6 are cross-sectional views of an organic light emitting diode display according to another exemplary embodiment, and a cross-sectional view of the organic light emitting diode display of FIG. 2 taken along lines III-III and IV-IV.

5 and 6, the organic light emitting diode display according to another exemplary embodiment of the present invention is mostly the same as the organic light emitting diode display according to the exemplary embodiment of the present invention, and the passivation layer 180 has planarization characteristics. It is formed from an inorganic film and is distinguished in that no separate blocking layer is formed.

The passivation layer 180 is formed of an inorganic layer such as silicon oxide (SiO 2), aluminum oxide (Al 2 O 2), or the like. In addition, the passivation layer 180 may be formed of a moisture absorbing organic layer having a property of absorbing moisture.

The organic light emitting diode display according to the present invention can block moisture flowing into the organic light emitting member by forming a blocking layer made of an inorganic layer on a protective film made of an organic layer.

In addition, by forming the protective film as an inorganic film, the moisture content of the protective film is minimized to improve the life of the organic light emitting member.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims (6)

Board, A first signal line formed on the substrate, A second signal line crossing the first signal line, A driving voltage line formed on the substrate and transferring a first voltage; A first thin film transistor connected to the first signal line and the second signal line, A second thin film transistor connected to the first thin film transistor and the driving voltage line; Passivation layers formed on the first and second thin film transistors, A blocking layer formed on the protective film, A first electrode formed on the blocking layer and connected to the second thin film transistor; A second electrode receiving a second voltage and facing the first electrode, And a light emitting member formed between the first electrode and the second electrode. In claim 1, The blocking layer is formed of an inorganic layer. In claim 1, The blocking layer is formed of a mixed thin film made of an inorganic insulator and an organic insulator. In claim 1, An organic light emitting display device in which protective layers and blocking layers are alternately formed on the protective layer and the blocking layer. In claim 1, And a partition wall surrounding the light emitting member. Board, A first signal line formed on the substrate, A second signal line crossing the first signal line, A driving voltage line formed on the substrate and transferring a first voltage; A first thin film transistor connected to the first signal line and the second signal line, A second thin film transistor connected to the first thin film transistor and the driving voltage line; A blocking layer formed on the first and second thin film transistors, A first electrode formed on the blocking layer and connected to the second thin film transistor; A second electrode receiving a second voltage and facing the first electrode, And a light emitting member formed between the first electrode and the second electrode, wherein the blocking layer is formed of an inorganic layer.

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